Strap metal bender



H. L. KOMBEREC ETAL STRAP METAL BENDER July 21, 1970 3,521,414

Filed Oct. 16, 1967 2 Sheets-Sheet l [FIGURE 3 Harold LKomberec,

Dillon K. Kilcup and Alfred T Smith,

yvamons.

\, ATTORNEY July 21, 1970 H, KOM BEREC ET AL 4 3,521,474

STRAP METAL 'BENDER Filed Oct. 16, 1967 2 Sheets-Sheet 2 lF/JGURE 4 Harold L. K0 be ac o'uon K. K10

and Alfre SmiT h, 1 vsrin l s. C

' ATTORNEX United States Patent 3,521,474 STRAP METAL BENDER Harold L. Komberec, N. 1511 Wall St. 99201; and

Dillon K. Kilcnp, W. 1012 Cleveland Ave. 99205,

both of Spokane, Wash.; and Alfred T. Smith, Otis Orchards, Wash. 99027 Filed Oct. 16, 1967, Ser. No. 675,612 Int. Cl. B21d 31/00 U.S. Cl. 72-319 9 Claims ABSTRACT OF THE DISCLOSURE A strap metal bender having holding jaws adjustably positionable relative each other, in both a forward-rearward plane and a vertical plane, to accept metal of differing thickness and a brake-jaw adjustably pivotable to pre-determined angular position to reproduce particular bends. The brake-jaw is provided with a replaceable work contacting anvil of relatively small work contacting area to lessen friction with the work surface. The upper holding jaw is removable to allow replacement especially with variously shaped forming arbors.

Our invention relates generally to a brake type device for forming strap metal by bending substantially perpendicularly to the longer dimension and more particularly to such a device that has means for adjustably positioning upper and lower holding jaws in forward-rearward direction relative each other; for adjustably positioning the holding jaws vertically to accept metal of different thicknesses and of adjustably regulating the angular motion of the brake-jaw to allow reproduction of identical strap iron forms. The face of the brake-jaw is provided with a relatively smaller replaceable, work contacting anvil to absorb the principal wear caused by the forming operation and making the operation easier by lessening friction between anvil and work. The forward work contacting portion of the upper holding jaw is removable to allow replacement if it become worn and to allow replacement with variously shaped forming arbors to create variously configurated arcuate forms.

In the metal forming arts it is oftentimes necessary to configure strap metal of relatively narrow width and great thickness into particular shapes of angular and arcuate form. Devices in the nature of sheet metal brakes have become known for this purpose but have not proven particularly effective, as their structure adapts them more for use with relatively thin, wide material. Various jig and die type presses are known to perform this operation, but they are generally not available in small metal working establishments where strap iron is most oftentimes formed. It is the purpose of this invention to provide an inexpensive bench-type tool especially for the small fabricator, to form strap iron into a variety of bendable configurations. In so doing it is:

A principal object of our invention to provide a brake type tool adapted particularly to form relatively thick, elongate strap metal to bendable forms with axis substantially perpendicular to the length of such metal.

A further object of our invention to provide such a tool that has cooperating opposed holding jaws adjustable in a forward-rearward dimension relative each other by means of an eccentric pivotable mounting of one of the jaws to allow metal of difiering thicknesses to be formed therein.

A further object of our invention to provide such holding jaws that are also adjustable in a vertical plane relative each other to allow the tool to frictionally hold strap metal of varying thicknesses.

A still further object of our invention to provide such a tool that has releasably positionable, motion-limiting means controlling the pivotable motion of the brake-jaw to allow reproducible forming of a plurality of similar elements.

A still further object of our invention to provide such a tool that has a unique brake-jaw with forwardly protruding anvil bar communicating with the part to be formed to provide less wear, a replaceable part and more easy formation of work because of lessened frictional engagement therewith.

A still further object of our invention to provide such a tool with upper holding jaws having a removable for ward portion to allow replacement with new nose elements or a particularly shaped arbor, is desired.

A still further object of our invention to provide such a tool that is of new and novel design, of simple and economic manufacture and operation, of rugged and durable nature and one that is otherwise adapted to the uses and purposes for which it is intended.

These and other objects of our invention will become apparent from consideration of the following specification and accompanying drawings which form a part of this application. In carrying out the objects of our invention, however, it is to he understood that its essential features are susceptible of change in design and arrangement of parts with only one preferred practical embodiment being illustrated and specified, as required.

In the accompanying drawings, wherein like numbers of reference refer to similar parts throughout:

FIG. 1 is an orthographic, right-side view of our metal bending tool, showing various of its parts, their configuration and relationship, from this aspect.

FIG. 2 is an orthographic top view of the invention illustrated in FIG. 1, showing its features from this aspect.

FIG. 3 is an elongate right lateral cross-sectional view of the invention of FIG. 2, taken on the line 3-3 thereon in the direction indicated by the arrows, to show various operating parts not apparent from the surface.

FIG. 4- is a left orthographic surface view of the in vention of FIG. 1 showing various elements from this aspect.

FIG. 5 is a right medial cross-sectional view of the invention of FIG. 2, taken on the line 55 thereon in the direction indicated by the arrows, to show further of the internal operating structure of the invention.

FIG. 6 is an isometric view of a particularly configured shaping arbor adapted for use in our bender.

Referring now to the drawings in more detail and particularly to that of FIG. 1, it will there be seen that our invention generally comprises base member 10, carrying lower jaw structure 11 and upper jaw structure 12 and pivotably mounting brake element 13.

Base 10 is a relatively narrow, elongate member providing support for the various elements of the tool and having in its rearward part 14 fastening plate 15, adjustably extendable by means of bolts 16, extending through elongate slot 17 and into threaded engagement with the base, to aid in positioning the device on some rigid structure (not shown). Commonly the tool would be positioned on an ordinary work bench to provide accessibility for a workman. Preferably, the whole device is formed from structurally durable metal of reasonable size to provide the rigidity necessary to withstand forces caused by the formation of the strap iron to be operated upon.

Lower jaw structure 11 is formed in the forwardmost part of base 10 with lower jaw 18 preferably formed, integrally, with base member 10. This lower jaw could be severable from the base and rigidly attached thereto, but construction of such nature is not necessary as this jaw has no severe wear and its configuration does not aid in the formation process. Lower jaw wedge 19 depends immediately below the lower surface of the lower jaw; it is formed with a rearwardly and upwardly sloping rearward surface 20 to cooperate in providing forward-rearward adjustment of the jaw structure. This lower jaw wedge 19 projects no further forwardly than lower jaw 18 and is structurally integral with, or rigidly attached to, base member 10.

Upper jaw structure 12 comprises forward upper jaw 21 structurally communicating between the laterally positioned paired, opposed upper jaw side plates 22, each adapted for vertical motion lateral of base member 10 to allow appropriate adjustment between the holding jaws.

Upper jaw arbor 57 is carried in way 58 in the forward lower portion of the upper jaw. This arbor is releasably positioned by plural bolts 59 extending through the upper jaw and into threaded engagement with the arbor. Since metal is formed by or about the arbor because of its forward positioning, it receives a relative great physical wear. Since it also is desirable to provide arbors of various shapes to aid in determining the final shape of a part to be formed, it is desirable that this element be readily removeable, though it must be rigidly attached.

Similar side plates 22 are pivotably journaled on upper jaw inner axle 23 so that they might pivot sufficiently to allow forward-rearward adjustability between the jaws. Inner axle 23 is eccentrically supported in upper jaw outer axle 24, slideably and pivotably carried by portion 25 of the upper jaw frame, structurally depending from the rearward undersurface of base 10, as illustrated.

Planer upper jaw adjustment plate 26 dependingly carried by upper jaw frame 22 has an arcuate lower surface to cooperate with adjustment arm 27 to releasably position the upper jaw relative the lower jaw. Adjustment arm 27 is an elongate element irrotationally carried by inner axle 23 and depending therefrom with medial surface 28 adapted to slideably engage the lower arcuate surface of adjustment element 26, to move eccentric outer axle 24 relative frame portion 25 and thusly upper jaw 21 in a forward or rearward direction relative the lower jaw. An adjustment screw 29 is provided in this adjustment arm to fixedly position it relative adjustment plate 26, as desired.

A spring dog 30 projects laterally inward from left side plate 22 to support compression spring 31 between the upper surface of the dog 30 and the lower surface of the base member 10 to bias the rearward portion of the side plate downward and thusly the forward portion to an upward position.

The jaw vertical spacing mechanism includes elongate alignment lever 32 irrotationally carried by axle 33 journaled in the medial portion of base 10. The lower split handle portion 34 of the alignment lever carries adjustment screw 35 to cooperate with adjustment plate 26 to releasably position the alignment lever relative thereto. The upper medial portion of the alignment lever has central elongate slot 36 slideably carrying pin 37 pivotably communicating with lower wedge arm 38, which in turn structurally communicates with lower wedge 39 in its rearward part. The upper surface of lower wedge 39 slideably communicates with the lower surface 20 of upper wedge 19. With this structure, as the alignment lever 32 moves forwardly or rearwardly, the wedges change relationship, the lower one moving up and down relative the upper, to thusly move the jaws relative each other in the vertical dimension.

Fastening dog 40, with forwardly curved surface 41 of the shape illustrated, is pivotably mounted on axle 42, carried in the lower forward portion of side plates 22 to communicate with the lower surface of lower Wedge 39. The fastening dog may be pivoted by manually manipulating the depending handle portion a in a forward direction to allow the upper jaw to raise to its uppermost position and may be lowered by rearward pivotal motion of the handle to frictionally fasten an element to be operated upon between the jaws.

Brake element 13 is an elongate brake bar 43 carried by cross plate 44 and having paired opposed ears 45 mounted upon jack shafts 46 carried by brake ears 47 of the upper forward extension of base member 10. Brake handle 53 depends from the medial portion of brake bar 43 to provide leverage for simple manual manipulation of the brake jaw. On the left side of the brake structure, lateral of the brake ear, is positioning plate 48 having inwardly projecting stop element 49 and circular, arcuate alignment slot SOL The positioning plate 48 is mounted upon axle 46 carried by the left brake ear. Adjustment screws 52 extend through alignment slot into threaded engagement with brake ear 47 therebelow to adjustably angularly position the positioning plate and thusly the stop element 49, to limit the pivotal motion of the brake bar upon engagement With the stop element.

The inwardly facing surface of brake bar 43 is provided with work contacting anvil 54 of a relatively thin, elongate nature, positioned to extend laterally somewhat above the lowermost portion of the brake face. This bar provides a hard, relatively narrow surface for communication with the work piece somewhat above and forwardly of its lowermost inward surface, to aid in the easier formation thereof. Preferably this member is swedged into proper position so that it can be removed and replaced when worn. Swedging is an appropriate means of communication between the pieces because the forces on the parts tend to enhance the communication rather than destroy it.

Having thusly described the structure of our invention, its operation may now be understood.

The device is first formed according to the teachings aforesaid and adjusted for the particular strap iron to be formed therein. The vertical distance between upper jaw and lower jaw is regulated to substantially the thickness of the material to be formed, so that the material will be held in rigid, frictional contact between the two jaws during formation. The forward-rearward positioning of upper jaw relative lower jaw is adjusted to at least the thickness of the material to be formed so that the brake jaw may operate upwardly without being sprung on its journal. With the machine in this position, the material to be formed is inserted between the upper and lower jaws to the appropriate position for formation and locked in this position by movement of fastening dog 40 in a rearward position. Thereupon to form the element, the positioning plate 48 is adjusted so that stop element 49 will stop the brake bar 43 at an appropriate radial position and the bar is then manually manipulated to this forming position and the element thusly formed.

Generally the method of formation recited will form an angled bend. An arcuate bend may be formed from plural spaced straight bends appropriating its form, if possible, or a shaped arbor may be used in the upper holding jaw, with the work piece bent about the forward surface 61 thereof to create the desired configuration. In this regard it is to be noted that the'brake jaw has a relatively great angle of rotation.

The foregoing description of our invention is necessarily of a detailed nature so that a specific embodiment of it might be set forth, as required, but it is to be understood that various changes in detail, rearrangement and manipulation of parts may be resorted to without departing from its spirit, essence or scope.

Having thusly described our invention, what we desire to protect by Letters Patent, and what We claim is:

1. A bending tool for strap metal comprising, in combination:

a planar, elongate base element, having means in its rearward portion for attachment to a supporting structure, and carrying in its forward part a transverse lower holding jaw;

a cooperating upper holding jaw having a transverse upper jaw element communicating between opposed laterally positioned side plates mounted laterally of said base element for slight motion, said pivotable mounting providing means for adjustment of forwardrearward positioning of said jaws relative each other;

a vertical jaw adjusting structure including a lever, pivotably depending from said base element forward of the pivotal mounting of said upper jaw side plates, communicating with a lower wedge slideably adjacent an upper wedge depending from the forward body structure to adjust the vertical dimension between said upper and lower jaw by motion of said wedges relative each other;

a locking dog pivotably carried by the upper jaw frame to communicate with the lower surface of said lower wedge to move said upper jaw from a mechanically biased upward position to a downward holding position; and

a brake element pivotably carried substantially coplanar with and forwardly of said lower holding jaw. I

2. The invention of claim 1 wherein the means for pivotally mounting said upper jaw include:

an inner shaft, carried between said upper jaw side plates in their rearward part, said inner shaft pivotably and eccentrically carried in an outer shaft at least pivotably carried by said base member; and

lever means communicating with said inner shaft to adjustably change the eccentricity of said inner shaft relative said body element.

3. The invention of claim 1 further characterized by said upper jaw member having:

a separable, forwardmost, laterally extending forming arbor releasably carried by said upper jaw structure by fastening means communicating therebetween.

4. The invention of claim 1 further characterized by the means of mechanically biasing said upper jaw relative said body member comprising:

a compression spring communicating between a lower surface of said body member and an upper surface of said upper jaw member'rearward of the pivot point therebetween.

5. The invention of claim 1 wherein said brake jaw is further characterized by:

a transverse relatively narrow work contacting anvil releasably positioned in the holding jaw facing surface thereof to communicate with a work piece forwardly and above the point of flexure therein.

6. The invention of claim 1 having a brake element position limiting device comprising:

a lateral positioning plate adjustably pivotably movable relative said body element and having an inwardly projecting stop dog adapted to communicate with said brake structure to limit pivotal motion of said brake jaw.

7. In a bending tool for strap metal having paired opposed holding jaws movably communicating by a base element to fasten strap metal therebetween and a brake element pivotably mounted forwardly of and substantially co-planar with the lower said holding jaw, the improvement in brake jaw comprising:

a generally transversely extending, relatively narrow work contacting anvil in the holding jaw facing surface of said brake element, said anvil positioned to communicate with a work piece somewhat forwardly and above the point of bending therein.

8. In a bending tool for strap metal having an elongate base terminating in a forward holding jaw and a cooperating upper holding jaw, including a transverse upper jaw element communicating between opposed side plates pivotably mounted laterally of said base, the improved pivotal mounting of aforesaid elements to allow limited forward and rearward motion therebetween, comprising:

an inner shaft carried between said upper jaw side plates, said inner shaft eccentrically, pivotably carried in an outer shaft pivotably and slideably, in a forwardrearward plane, carried by said base; and

lever means communicating with one of said shafts to adjustably change the eccentricity of said inner shaft relative said body element.

9. In a bending tool for strap metal, having an elongate base terminating in a forward holding jaw and a cooperating upper holding jaw, including a transverse upper jaw element communicating between opposed side plates pivotably mounted laterally of said base, the improved structure to adjust vertical distance between said holding jaws, comprising:

a first wedge depending from said base, forwardly of the pivotal mounting of said upper jaw structure with its angled face downward;

a second wedge slideably adjacent the lower surface of said first wedge to change vertical positioning upon forward-rearward motion;

lever means of moving said second wedge in a forwardrearward direction, mechanical means communicating from the lower surface of said second wedge to said upper jaw structure to move said upper jaw structure in response to motions of said second wedge; and

means of mechanically biasing said upper jaw structure to a normally upward position.

References Cited UNITED STATES PATENTS 674,908 5/1901 Dreisvogt 72319 960,910 6/ 1910 Hazen 72319 1,162,050 11/1915 Goeler' 72319 2,028,869 1/ 1936 Jensen 72319 2,438,319 3/1948 Kilham 72-319 3,359,771 12/ 1967 Meyerchick 72319 MILTON S. MEHR, Primary Examiner US. Cl. X.R. 72-411 

